Radio frequency users such as commercial telecommunication providers typically use radio frequencies that the government has designated to be available for public and commercial use. A large range of the radio frequency spectrum usable for communications is reserved for use by the government. See, e.g., http://www.ntia.doc.gov/page/2011/united-states-frequency-allocation-chart. Additional background materials are available in the “Report to the President Realizing the Full Potential of Government-Held Spectrum to Spur Economic Growth” from the Executive Office of the President/President's Council of Advisors on Science and Technology dated July 2012, available at http://www.whitehouse.gov/sites/default/files/microsites/ostp/pcast_spectrum_report_final_july_20_2012.pdf.